Field of the Invention
The present invention concerns the field of magnetic resonance imaging, in particular an end ring port structure of an atypical radio-frequency (RF) coil, an RF coil assembly, and a magnetic resonance imaging system having such an RF coil assembly.
Description of the Prior Art
Magnetic resonance imaging (MRI) is an imaging modality involving biomagnetics and nuclear spin, which has advanced rapidly with the development of computer technology, electronic circuit technology and superconductor technology. MRI uses a magnetic field and radio frequency (RF) pulses to induce oscillation of processing hydrogen nuclei (i.e. H+) in human tissue, so as to generate RF signals that are processed by a computer to form an image. If an object is placed in a magnetic field and irradiated by suitable electromagnetic energy to produce resonance therein, and electromagnetic signals emitted thereby are then analyzed, it is possible to identify the positions and types of the atomic nuclei of which the object is composed. On this basis, a precise three-dimensional image of the interior of the object can be made. For instance, a moving picture of contiguous slices can be obtained by performing an MRI scan of the human brain, starting at the top of the head and continuing all the way to the foot.
In an MRI system, an RF coil emits RF pulses to bring about magnetic resonance. A local coil receives the magnetic resonance signal, and sends the magnetic resonance signal to a reception coil channel selector (RCCS) and a receiver. As the front end of the signal reception chain, an RF coil plays a decisive role in imaging quality. Compared with other components, RF coils have the advantages of being easy to develop and optimize, and for this reason have always been a focus of activity in the MRI research field. RF coils generally include typical coils and atypical coils. An end ring of a typical coil is circular, whereas an end ring of an atypical coil is non-circular.
In the prior art, each port of a typical coil spans one capacitance position, and only one capacitor is arranged at the spanned capacitance position. By arranging two ports on an end ring at an interval of 90 degrees, electrical orthogonality between the ports can be realized, so as to optimize the homogeneity of the RF field (B1 field).
However, in the case of an end ring port structure of an atypical coil, corresponding research is lacking.